Optical imaging lens

ABSTRACT

An optical imaging lens includes a first lens of negative refractive power, a second lens of negative refractive power and of an image-side surface with a concave portion near its optical-axis, a third lens of an object-side surface with a convex portion near its optical-axis and an image-side surface with a convex portion near its optical-axis, a fourth lens of an object-side surface with a convex portion near its optical-axis, a fifth lens of an object-side surface with a concave portion near its periphery and an image-side surface with a concave portion in a vicinity of its optical-axis and a six lens of an image-side surface with a convex portion near its optical-axis. ALT is a total thickness of all six lens elements, AAG is a sum of all five air gaps and the first lens element has a first lens element thickness T1 to satisfy ALT/T1≤6.70 or AAG/T1≤4.71.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens. Specifically speaking, the present invention is directed to an optical imaging lens for the application of dual band of visible light as well as NIR (near infrared) for use in portable electronic devices such as mobile phones, cameras, tablet personal computers, personal digital assistants (PDA), vehicles, or rescue devices for recording videos.

2. Description of the Prior Art

The applications of an optical imaging lens is not only limited to take pictures and to record videos but also for the environmental surveillance, the dashboard cameras, the VR trackers or the face recognition. With the increasing applications, one single device may need to install at least one visible light imaging lens as well as an NIR imaging lens at the same time. Such demands for the double imaging lens sets not only increase the cost as well as the complication of the device but also influence the appearance design of the device.

The first thing to overcome in order to design a dual band optical imaging lens is to solve the problem of respective focusing of different wavebands. When the object distance changes, the voice coil motor (VCM) in the lens set module makes the position of the sensor change to focus. When the light has different wavebands, the sensor has different position to focus.

It is a main pending problem to design a dual band optical imaging lens and to go with a sensor of RGB & IR wavebands to capture the imaging rays of RGB & IR light at the same time and to simultaneously focus all light at the same plane. In addition to solving these problems of simultaneous focusing and to maintain good imaging quality at the same time, the half field of view is also needed to be larger for the detection of larger space.

However, a larger half field of view not only lowers the imaging quality but also jeopardizes the focusing ability of the dual band rays. In accordance with the above prior art, it is another issue to increase the half field of view for the design of the dual band optical imaging lens.

SUMMARY OF THE INVENTION

In the light of the above, the present invention accordingly proposes an optical imaging lens which has increased half field of view, is capable of dual-wavebands capture and maintains appropriate lens set length. The optical imaging lens of six lens elements of the present invention from an object side toward an image side in order along an optical axis has a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element. Each lens element respectively has an object-side surface which faces toward an object side to allow an imaging ray to pass through as well as an image-side surface which faces toward an image side to allow the imaging ray to pass through.

In one aspect of the present invention, the first lens element has negative refractive power. The second lens element has negative refractive power. The object-side surface of the third lens element has a convex portion in a vicinity of the optical-axis and the image-side surface of the third lens element has a convex portion in a vicinity of the optical-axis. The object-side surface of the fourth lens element has a convex portion in a vicinity of the optical-axis. The object-side surface of the fifth lens element has a concave portion in a vicinity of its periphery and the image-side surface of the fifth lens element has a concave portion in a vicinity of the optical-axis. The image-side surface of the sixth lens element has a convex portion in a vicinity of the optical-axis. The optical imaging lens exclusively has six lens elements with refractive power. ALT is a total thickness of all six lens elements and the first lens element has a first lens element thickness T1 to satisfy ALT/T1≤6.70.

In another aspect of the present invention, the first lens element has negative refractive power. The second lens element has negative refractive power and the image-side surface of the second lens element has a concave portion in a vicinity of the optical-axis. The object-side surface of the third lens element has a convex portion in a vicinity of the optical-axis and the image-side surface of the third lens element has a convex portion in a vicinity of the optical-axis. The object-side surface of the fourth lens element has a convex portion in a vicinity of the optical-axis. The object-side surface of the fifth lens element has a concave portion in a vicinity of its periphery and the image-side surface of the fifth lens element has a concave portion in a vicinity of the optical-axis. The image-side surface of the sixth lens element has a convex portion in a vicinity of the optical-axis. The optical imaging lens exclusively has six lens elements with refractive power. AAG is a sum of all five air gaps between each lens element from the first lens element to the sixth lens element and the first lens element has a first lens element thickness T1 to satisfy AAG/T1≤4.71.

In the optical imaging lens of six lens elements of the present invention, EFL is an effective focal length of the optical imaging lens set, the second lens element has a second lens element thickness T2 along the optical axis, the third lens element has a third lens element thickness T3 along the optical axis, the fourth lens element has a fourth lens element thickness T4 along the optical axis and the fifth lens element has a fifth lens element thickness T5 along the optical axis to satisfy (T2+T3+T4+T5)/EFL≤5.57.

In the optical imaging lens of six lens elements of the present invention, the sixth lens element has a sixth lens element thickness T6 along the optical axis to satisfy (T2+T3+T5+T6)/T1≤4.41.

In the optical imaging lens of six lens elements of the present invention, an air gap G12 between the first lens element and the second lens element along the optical axis to satisfy (G12+T2+T4)/T3≤2.50.

In the optical imaging lens of six lens elements of the present invention, an air gap G23 between the second lens element and the third lens element along the optical axis, an air gap G34 between the third lens element and the fourth lens element along the optical axis, an air gap G45 between the fourth lens element and the fifth lens element along the optical axis and an air gap G56 between the fifth lens element and the sixth lens element along the optical axis to satisfy (G12+G23+G56)/(G34+G45)≤6.01.

The optical imaging lens of four lens elements of the present invention satisfies (G12+T2+G23+T3)/T1≤5.81.

The optical imaging lens of four lens elements of the present invention satisfies (T2+G23+T4+T6)/T1≤5.00.

The optical imaging lens of four lens elements of the present invention satisfies ALT/T3≤3.80.

In the optical imaging lens of six lens elements of the present invention, TL is a distance between the object-side surface of the first lens element and the image-side surface of the sixth lens element along the optical axis to satisfy TL/T1≤11.50.

In the optical imaging lens of six lens elements of the present invention, the first lens element has an Abbe number υ1, the second lens element has an Abbe number υ2, the fourth lens element an Abbe number υ4 and the fifth lens element has an Abbe number υ5 to satisfy υ1+υ2>υ4+υ5.

The optical imaging lens of four lens elements of the present invention satisfies (T2+T3+T5+T6)/EFL≤5.47.

The optical imaging lens of four lens elements of the present invention satisfies (T2+T3+T4+T5)/T1≤4.51.

The optical imaging lens of four lens elements of the present invention satisfies (G12+T4+T5)/T3≤2.30.

In the optical imaging lens of six lens elements of the present invention, BFL is a distance between the image-side surface of the sixth lens element and an image plane along the optical axis to satisfy (G12+G56+BFL)/(G34+G45)≤7.00.

The optical imaging lens of four lens elements of the present invention satisfies (T4+G45+T5+G56+T6)/T1≤3.70.

The optical imaging lens of four lens elements of the present invention satisfies (T2+G23+T4+T6)/(G34+G45)≤7.00.

The optical imaging lens of four lens elements of the present invention satisfies AAG/T3≤2.80.

The optical imaging lens of four lens elements of the present invention satisfies TL/T3≤5.42.

In the optical imaging lens of six lens elements of the present invention, the sixth lens element has an Abbe number υ6 to satisfy υ1+υ4>υ5+υ6.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrates the methods for determining the surface shapes and for determining one region is a region in a vicinity of the optical axis or the region in a vicinity of its periphery of one lens element.

FIG. 6 illustrates a first example of the optical imaging lens of the present invention.

FIG. 7A illustrates the longitudinal spherical aberration on the image plane of the first example.

FIG. 7B illustrates the astigmatic aberration on the sagittal direction of the first example.

FIG. 7C illustrates the astigmatic aberration on the tangential direction of the first example.

FIG. 7D illustrates the distortion aberration of the first example.

FIG. 8 illustrates a second example of the optical imaging lens of six lens elements of the present invention.

FIG. 9A illustrates the longitudinal spherical aberration on the image plane of the second example.

FIG. 9B illustrates the astigmatic aberration on the sagittal direction of the second example.

FIG. 9C illustrates the astigmatic aberration on the tangential direction of the second example.

FIG. 9D illustrates the distortion aberration of the second example.

FIG. 10 illustrates a third example of the optical imaging lens of six lens elements of the present invention.

FIG. 11A illustrates the longitudinal spherical aberration on the image plane of the third example.

FIG. 11B illustrates the astigmatic aberration on the sagittal direction of the third example.

FIG. 11C illustrates the astigmatic aberration on the tangential direction of the third example.

FIG. 11D illustrates the distortion aberration of the third example.

FIG. 12 illustrates a fourth example of the optical imaging lens of six lens elements of the present invention.

FIG. 13A illustrates the longitudinal spherical aberration on the image plane of the fourth example.

FIG. 13B illustrates the astigmatic aberration on the sagittal direction of the fourth example.

FIG. 13C illustrates the astigmatic aberration on the tangential direction of the fourth example.

FIG. 13D illustrates the distortion aberration of the fourth example.

FIG. 14 illustrates a fifth example of the optical imaging lens of six lens elements of the present invention.

FIG. 15A illustrates the longitudinal spherical aberration on the image plane of the fifth example.

FIG. 15B illustrates the astigmatic aberration on the sagittal direction of the fifth example.

FIG. 15C illustrates the astigmatic aberration on the tangential direction of the fifth example.

FIG. 15D illustrates the distortion aberration of the fifth example.

FIG. 16 illustrates a sixth example of the optical imaging lens of six lens elements of the present invention.

FIG. 17A illustrates the longitudinal spherical aberration on the image plane of the sixth example.

FIG. 17B illustrates the astigmatic aberration on the sagittal direction of the sixth example.

FIG. 17C illustrates the astigmatic aberration on the tangential direction of the sixth example.

FIG. 17D illustrates the distortion aberration of the sixth example.

FIG. 18 illustrates a seventh example of the optical imaging lens of six lens elements of the present invention.

FIG. 19A illustrates the longitudinal spherical aberration on the image plane of the seventh example.

FIG. 19B illustrates the astigmatic aberration on the sagittal direction of the seventh example.

FIG. 19C illustrates the astigmatic aberration on the tangential direction of the seventh example.

FIG. 19D illustrates the distortion aberration of the seventh example.

FIG. 20 illustrates an eighth example of the optical imaging lens of six lens elements of the present invention.

FIG. 21A illustrates the longitudinal spherical aberration on the image plane of the eighth example.

FIG. 21B illustrates the astigmatic aberration on the sagittal direction of the eighth example.

FIG. 21C illustrates the astigmatic aberration on the tangential direction of the eighth example.

FIG. 21D illustrates the distortion aberration of the eighth example.

FIG. 22 illustrates a ninth example of the optical imaging lens of six lens elements of the present invention.

FIG. 23A illustrates the longitudinal spherical aberration on the image plane of the ninth example.

FIG. 23B illustrates the astigmatic aberration on the sagittal direction of the ninth example.

FIG. 23C illustrates the astigmatic aberration on the tangential direction of the ninth example.

FIG. 23D illustrates the distortion aberration of the ninth example.

FIG. 24 illustrates a tenth example of the optical imaging lens of six lens elements of the present invention.

FIG. 25A illustrates the longitudinal spherical aberration on the image plane of the tenth example.

FIG. 25B illustrates the astigmatic aberration on the sagittal direction of the tenth example.

FIG. 25C illustrates the astigmatic aberration on the tangential direction of the tenth example.

FIG. 25D illustrates the distortion aberration of the tenth example.

FIG. 26 illustrates an eleventh example of the optical imaging lens of six lens elements of the present invention.

FIG. 27A illustrates the longitudinal spherical aberration on the image plane of the eleventh example.

FIG. 27B illustrates the astigmatic aberration on the sagittal direction of the eleventh example.

FIG. 27C illustrates the astigmatic aberration on the tangential direction of the eleventh example.

FIG. 27D illustrates the distortion aberration of the eleventh example.

FIG. 28 illustrates a twelfth example of the optical imaging lens of six lens elements of the present invention.

FIG. 29A illustrates the longitudinal spherical aberration on the image plane of the twelfth example.

FIG. 29B illustrates the astigmatic aberration on the sagittal direction of the eleventh example.

FIG. 29C illustrates the astigmatic aberration on the tangential direction of the twelfth example.

FIG. 29D illustrates the distortion aberration of the twelfth example.

FIG. 30 shows the optical data of the first example of the optical imaging lens.

FIG. 31 shows the aspheric surface data of the first example.

FIG. 32 shows the optical data of the second example of the optical imaging lens.

FIG. 33 shows the aspheric surface data of the second example.

FIG. 34 shows the optical data of the third example of the optical imaging lens.

FIG. 35 shows the aspheric surface data of the third example.

FIG. 36 shows the optical data of the fourth example of the optical imaging lens.

FIG. 37 shows the aspheric surface data of the fourth example.

FIG. 38 shows the optical data of the fifth example of the optical imaging lens.

FIG. 39 shows the aspheric surface data of the fifth example.

FIG. 40 shows the optical data of the sixth example of the optical imaging lens.

FIG. 41 shows the aspheric surface data of the sixth example.

FIG. 42 shows the optical data of the seventh example of the optical imaging lens.

FIG. 43 shows the aspheric surface data of the seventh example.

FIG. 44 shows the optical data of the eighth example of the optical imaging lens.

FIG. 45 shows the aspheric surface data of the eighth example.

FIG. 46 shows the optical data of the ninth example of the optical imaging lens.

FIG. 47 shows the aspheric surface data of the ninth example.

FIG. 48 shows the optical data of the tenth example of the optical imaging lens.

FIG. 49 shows the aspheric surface data of the tenth example.

FIG. 50 shows the optical data of the eleventh example of the optical imaging lens.

FIG. 51 shows the aspheric surface data of the eleventh example.

FIG. 52 shows the optical data of the twelfth example of the optical imaging lens.

FIG. 53 shows the aspheric surface data of the twelfth example.

FIG. 54 shows some important ratios in the examples.

FIG. 55 shows some important ratios in the examples.

DETAILED DESCRIPTION

Before the detailed description of the present invention, the first thing to be noticed is that in the present invention, similar (not necessarily identical) elements are labeled as the same numeral references. In the entire present specification, “a certain lens element has negative/positive refractive power” refers to the portion in a vicinity of the optical axis of the lens element has negative/positive refractive power calculated by Gaussian optical theory. An object-side/image-side surface refers to the region which allows imaging light passing through, in the drawing, imaging light includes Lc (chief ray) and Lm (marginal ray). As shown in FIG. 1, the optical axis is “I” and the lens element is symmetrical with respect to the optical axis I. The region A that near the optical axis and for light to pass through is the region in a vicinity of the optical axis, and the region C that the marginal ray passing through is the region in a vicinity of a certain lens element's periphery. In addition, the lens element may include an extension portion E for the lens element to be installed in an optical imaging lens (that is the region outside the region C perpendicular to the optical axis). Ideally speaking, no light would pass through the extension portion, and the actual structure and shape of the extension portion is not limited to this and may have other variations. For the reason of simplicity, the extension portion is not illustrated in the following examples. More, precisely, the method for determining the surface shapes or the region in a vicinity of the optical axis, the region in a vicinity of its periphery and other regions is described in the following paragraphs:

1. FIG. 1 is a radial cross-sectional view of a lens element. Before determining boundaries of those aforesaid portions, two referential points should be defined first, middle point and conversion point. The middle point of a surface of a lens element is a point of intersection of that surface and the optical axis. The conversion point is a point on a surface of a lens element, where the tangent line of that point is perpendicular to the optical axis. Additionally, if multiple conversion points appear on one single surface, then these conversion points are sequentially named along the radial direction of the surface with numbers starting from the first conversion point. For instance, the first conversion point (closest one to the optical axis), the second conversion point, and the N^(th) conversion point (farthest one to the optical axis within the scope of the clear aperture of the surface). The portion of a surface of the lens element between the middle point and the first conversion point is defined as the portion in a vicinity of the optical axis. The portion located radially outside of the N^(th) conversion point (but still within the scope of the clear aperture) is defined as the portion in a vicinity of a periphery of the lens element. In some embodiments, there are other portions existing between the portion in a vicinity of the optical axis and the portion in a vicinity of a periphery of the lens element; the numbers of portions depend on the numbers of the conversion point(s). In addition, the radius of the clear aperture (or a so-called effective radius) of a surface is defined as the radial distance from the optical axis I to a point of intersection of the marginal ray Lm and the surface of the lens element. 2. Referring to FIG. 2, determining the shape of a portion is convex or concave depends on whether a collimated ray passing through that portion converges or diverges. That is, while applying a collimated ray to a portion to be determined in terms of shape, the collimated ray passing through that portion will be bended and the ray itself or its extension line will eventually meet the optical axis. The shape of that portion can be determined by whether the ray or its extension line meets (intersects) the optical axis (focal point) at the object-side or image-side. For instance, if the ray itself intersects the optical axis at the image side of the lens element after passing through a portion, i.e. the focal point of this ray is at the image side (see point R in FIG. 2), the portion will be determined as having a convex shape. On the contrary, if the ray diverges after passing through a portion, the extension line of the ray intersects the optical axis at the object side of the lens element, i.e. the focal point of the ray is at the object side (see point M in FIG. 2), that portion will be determined as having a concave shape. Therefore, referring to FIG. 2, the portion between the middle point and the first conversion point has a convex shape, the portion located radially outside of the first conversion point has a concave shape, and the first conversion point is the point where the portion having a convex shape changes to the portion having a concave shape, namely the border of two adjacent portions. Alternatively, there is another common way for a person with ordinary skill in the art to tell whether a portion in a vicinity of the optical axis has a convex or concave shape by referring to the sign of an “R” value, which is the (paraxial) radius of curvature of a lens surface. The R value is commonly used in conventional optical design software such as Zemax and CodeV. The R value usually appears in the lens data sheet in the software. For an object-side surface, positive R means that the object-side surface is convex, and negative R means that the object-side surface is concave. Conversely, for an image-side surface, positive R means that the image-side surface is concave, and negative R means that the image-side surface is convex. The result found by using this method should be consistent as by using the other way mentioned above, which determines surface shapes by referring to whether the focal point of a collimated ray is at the object side or the image side. 3. For none conversion point cases, the portion in a vicinity of the optical axis is defined as the portion between 0˜50% of the effective radius (radius of the clear aperture) of the surface, whereas the portion in a vicinity of a periphery of the lens element is defined as the portion between 50˜100% of effective radius (radius of the clear aperture) of the surface.

Referring to the first example depicted in FIG. 3, only one conversion point, namely a first conversion point, appears within the clear aperture of the image-side surface of the lens element. Portion I is a portion in a vicinity of the optical axis, and portion II is a portion in a vicinity of a periphery of the lens element. The portion in a vicinity of the optical axis is determined as having a concave surface due to the R value at the image-side surface of the lens element is positive. The shape of the portion in a vicinity of a periphery of the lens element is different from that of the radially inner adjacent portion, i.e. the shape of the portion in a vicinity of a periphery of the lens element is different from the shape of the portion in a vicinity of the optical axis; the portion in a vicinity of a periphery of the lens element has a convex shape.

Referring to the second example depicted in FIG. 4, a first conversion point and a second conversion point exist on the object-side surface (within the clear aperture) of a lens element. In which portion I is the portion in a vicinity of the optical axis, and portion III is the portion in a vicinity of a periphery of the lens element. The portion in a vicinity of the optical axis has a convex shape because the R value at the object-side surface of the lens element is positive. The portion in a vicinity of a periphery of the lens element (portion III) has a convex shape. What is more, there is another portion having a concave shape existing between the first and second conversion point (portion II).

Referring to a third example depicted in FIG. 5, no conversion point exists on the object-side surface of the lens element. In this case, the portion between 0˜50% of the effective radius (radius of the clear aperture) is determined as the portion in a vicinity of the optical axis, and the portion between 50˜100% of the effective radius is determined as the portion in a vicinity of a periphery of the lens element. The portion in a vicinity of the optical axis of the object-side surface of the lens element is determined as having a convex shape due to its positive R value, and the portion in a vicinity of a periphery of the lens element is determined as having a convex shape as well.

As shown in FIG. 6, the optical imaging lens 1 of six lens elements of the present invention, sequentially located from an object side 2 (where an object is located) to an image side 3 along an optical axis 4, has a first lens element 10, a second lens element 20, a third lens element 30, a fourth lens element 40, a fifth lens element 50, a sixth lens element 60, a filter 70 and an image plane 71. Generally speaking, the first lens element 10, the second lens element 20, the third lens element 30, the fourth lens element 40, the fifth lens element 50 and the sixth lens element 60 may be made of a transparent plastic material but the present invention is not limited to this, and each has an appropriate refractive power. For example, optionally, the first lens element 10 may be made of a transparent plastic material or of transparent glass. There are exclusively six lens elements, which means the first lens element 10, the second lens element 20, the third lens element 30, the fourth lens element 40, the fifth lens element 50 and the sixth lens element 60, with refractive power in the optical imaging lens 1 of the present invention. The optical axis 4 is the optical axis of the entire optical imaging lens 1, and the optical axis of each of the lens elements coincides with the optical axis of the optical imaging lens 1.

Furthermore, the optical imaging lens 1 includes an aperture stop (ape. stop) 80 disposed in an appropriate position. In FIG. 6, the aperture stop 80 is disposed between the third lens element 30 and the fourth lens element 40. When light emitted or reflected by an object (not shown) which is located at the object side 2 enters the optical imaging lens 1 of the present invention, it forms a clear and sharp image on the image plane 71 at the image side 3 after passing through the first lens element 10, the second lens element 20, the third lens element 30, the aperture stop 80, the fourth lens element 40, the fifth lens element 50, the sixth lens element 60 and the filter 70. In one embodiments of the present invention, the optional filter 70 may be a filter of various suitable functions, for example, the filter 70 may be a cut filter of a specific wavelength, placed between the image-side surface 62 of the sixth lens element 60 and the image plane 71.

Each lens element in the optical imaging lens 1 of the present invention has an object-side surface facing toward the object side 2 as well as an image-side surface facing toward the image side 3. For example, the first lens element 10 has an object-side surface 11 and an image-side surface 12; the second lens element 20 has an object-side surface 21 and an image-side surface 22; the third lens element 30 has an object-side surface 31 and an image-side surface 32; the fourth lens element 40 has an object-side surface 41 and an image-side surface 42; the fifth lens element 50 has an object-side surface 51 and an image-side surface 52; and the sixth lens element 60 has an object-side surface 61 and an image-side surface 62. In addition, each object-side surface and image-side surface in the optical imaging lens 1 of the present invention has a portion (or region) in a vicinity of its periphery (periphery region) away from the optical axis 4 as well as a portion in a vicinity of the optical axis (optical axis portion) close to the optical axis 4.

Each lens element in the optical imaging lens 1 of the present invention further has a central thickness T on the optical axis 4. For example, the first lens element 10 has a first lens element thickness T1, the second lens element 20 has a second lens element thickness T2, the third lens element 30 has a third lens element thickness T3, the fourth lens element 40 has a fourth lens element thickness T4, the fifth lens element 50 has a fifth lens element thickness T5, the sixth lens element 60 has a sixth lens element thickness T6. Therefore, the total thickness of all the lens elements in the optical imaging lens 1 along the optical axis 4 is ALT=T1+T2+T3+T4+T5+T6.

In addition, between two adjacent lens elements in the optical imaging lens 1 of the present invention there may be an air gap along the optical axis 4. For example, there is an air gap G12 disposed between the first lens element 10 and the second lens element 20, an air gap G23 disposed between the second lens element 20 and the third lens element 30, an air gap G34 disposed between the third lens element 30 and the fourth lens element 40, an air gap G45 disposed between the fourth lens element 40 and the fifth lens element 50 as well as there is an air gap G56 disposed between the fifth lens element 50 and the sixth lens element 60. Therefore, the sum of total five air gaps between adjacent lens elements from the first lens element 10 to the sixth lens element 60 along the optical axis 4 is AAG=G12+G23+G34+G45+G56.

In addition, the distance from the object-side surface 11 of the first lens element 10 to the image-side surface 62 of the sixth lens element 60 along the optical axis 4 is TL. The distance between the object-side surface 11 of the first lens element 10 to the image plane 71, namely the total length of the optical imaging lens along the optical axis 4 is TTL; the effective focal length of the optical imaging lens is EFL; the distance between the image-side surface 62 of the sixth lens element 60 and the image plane 71 along the optical axis 4 is BFL.

Furthermore, the focal length of the first lens element 10 is f1; the focal length of the second lens element 20 is f2; the focal length of the third lens element 30 is f3; the focal length of the fourth lens element 40 is f4; the focal length of the fifth lens element 50 is f5; the focal length of the sixth lens element 60 is f6; the refractive index of the first lens element 10 is n1; the refractive index of the second lens element 20 is n2; the refractive index of the third lens element 30 is n3; the refractive index of the fourth lens element 40 is n4; the refractive index of the fifth lens element 50 is n5; the refractive index of the sixth lens element 60 is n6; the Abbe number of the first lens element 10 is υ1; the Abbe number of the second lens element 20 is υ2; the Abbe number of the third lens element 30 is υ3; and the Abbe number of the fourth lens element 40 is υ4; the Abbe number of the fifth lens element 50 is υ5; and the Abbe number of the sixth lens element 60 is υ6.

First Example

Please refer to FIG. 6 which illustrates the first example of the optical imaging lens 1 of the present invention. Please refer to FIG. 7A for the longitudinal spherical aberration on the image plane 71 of the first example; please refer to FIG. 7B for the astigmatic field aberration on the sagittal direction; please refer to FIG. 7C for the astigmatic field aberration on the tangential direction, and please refer to FIG. 7D for the distortion aberration. The Y axis of the spherical aberration in each example is “field of view” for 1.0. The Y axis of the astigmatic field and the distortion in each example stands for “image height”, which is 0.825 mm.

The optical imaging lens 1 of the first example has six lens elements 10 to 60 with refractive power. The optical imaging lens 1 also has a filter 70, an aperture stop 80, and an image plane 71. The aperture stop 80 is provided between the third lens element 30 and the fourth lens element 40. The filter 70 may be used for preventing specific wavelength light reaching the image plane to adversely affect the imaging quality.

The first lens element 10 is made of a plastic material and has negative refractive power. The object-side surface 11 facing toward the object side 2 has a convex portion 13 in the vicinity of the optical axis and a convex portion 14 in a vicinity of its periphery. The image-side surface 12 facing toward the image side 3 has a concave portion 16 in the vicinity of the optical axis and a concave portion 17 in a vicinity of its periphery. Besides, both the object-side surface 11 and the image-side 12 of the first lens element 10 are spherical surfaces.

The second lens element 20 has negative refractive power. The object-side surface 21 facing toward the object side 2 has a concave portion 23 in the vicinity of the optical axis 4 and a concave portion 24 in a vicinity of its periphery. The image-side surface 22 facing toward the image side 3 has a concave portion 26 in the vicinity of the optical axis 4 and a concave portion 27 in a vicinity of its periphery. Besides, both the object-side surface 21 and the image-side 22 of the second lens element 20 are aspherical surfaces.

The third lens element 30 has positive refractive power. The object-side surface 31 facing toward the object side 2 has a convex portion 33 in the vicinity of the optical axis and a convex portion 34 in a vicinity of its periphery. The image-side surface 32 facing toward the image side 3 has a convex portion 36 in the vicinity of the optical axis 4 and a convex portion 37 in a vicinity of its periphery. Besides, both the object-side surface 31 and the image-side 32 of the third lens element 30 are aspherical surfaces.

The fourth lens element 40 has positive refractive power. The object-side surface 41 facing toward the object side 2 has a convex portion 43 in the vicinity of the optical axis 4 and a convex portion 44 in a vicinity of its periphery. The image-side surface 42 facing toward the image side 3 has a convex portion 46 in the vicinity of the optical axis 4 and a convex portion 47 in a vicinity of its periphery. Besides, both the object-side surface 41 and the image-side 42 of the fourth lens element 40 are aspherical surfaces.

The fifth lens element 50 has negative refractive power. The object-side surface 51 facing toward the object side 2 has a concave portion 53 in the vicinity of the optical axis 4 and a concave portion 54 in a vicinity of its periphery. The image-side surface 52 facing toward the image side 3 has a concave portion 56 in the vicinity of the optical axis 4 and a concave portion 57 in a vicinity of its periphery. Besides, both the object-side surface 51 and the image-side 52 of the fifth lens element 50 are aspherical surfaces.

The sixth lens element 60 has positive refractive power. The object-side surface 61 facing toward the object side 2 has a convex portion 63 in the vicinity of the optical axis and a convex portion 64 in a vicinity of its periphery. The image-side surface 62 facing toward the image side 3 has a convex portion 66 in the vicinity of the optical axis and a convex portion 67 in a vicinity of its periphery. Besides, both the object-side surface 61 and the image-side 62 of the sixth lens element 60 are aspherical surfaces. The filter 70 is disposed between the image-side 62 of the sixth lens element 60 and the image plane 71.

In the first lens element 10, the second lens element 20, the third lens element 30, the fourth lens element 40, the fifth lens element 50 and the sixth lens element 60 of the optical imaging lens element 1 of the present invention, there are 12 surfaces, such as the object-side surfaces 11/21/31/41/51/61 and the image-side surfaces 12/22/32/42/52/62. If a surface is aspherical, these aspheric coefficients are defined according to the following formula:

${Z(Y)} = {{\frac{Y^{2}}{R}\text{/}\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\; {a_{i} \times Y^{i}}}}$

In which: R represents the curvature radius of the lens element surface; Z represents the depth of an aspherical surface (the perpendicular distance between the point of the aspherical surface at a distance Y from the optical axis and the tangent plane of the vertex on the optical axis of the aspherical surface); Y represents a vertical distance from a point on the aspherical surface to the optical axis; K is a conic constant; a_(i) is the aspheric coefficient of the i^(th) order.

The optical data of the first example of the optical imaging lens 1 are shown in FIG. 30 while the aspheric surface data are shown in FIG. 31. There is a virtual reference surface of infinite curvature radius (not shown), VRS for short, disposed between the filter 70 and the image plane 71. In the present examples of the optical imaging lens, the f-number of the entire optical lens element system is Fno, EFL is the effective focal length, HFOV stands for the half field of view which is half of the field of view of the entire optical imaging lens 1, and the unit for the curvature radius, the thickness and the focal length is in millimeters (mm). TTL is 7.395 mm. Fno is 2.28. The image height (IMH) is 0.825 mm. HFOV is 75 degrees.

Second Example

Please refer to FIG. 8 which illustrates the second example of the optical imaging lens 1 of the present invention. It is noted that from the second example to the following examples, in order to simplify the figures, only the components different from what the first example has, and the basic lens elements will be labeled in figures. Other components that are the same as what the first example has, such as the object-side surface, the image-side surface, the portion in a vicinity of the optical axis and the portion in a vicinity of its periphery will be omitted in the following examples. Please refer to FIG. 9A for the longitudinal spherical aberration on the image plane 71 of the second example, please refer to FIG. 9B for the astigmatic aberration on the sagittal direction, please refer to FIG. 9C for the astigmatic aberration on the tangential direction, and please refer to FIG. 9D for the distortion aberration. The components in the second example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in the second example, the first lens element 10 is made of transparent glass.

The optical data of the second example of the optical imaging lens are shown in FIG. 32 while the aspheric surface data are shown in FIG. 33. TTL is 7.866 mm. Fno is 2.28. The image height is 0.853 mm. HFOV is 75 degrees. In particular, the aberration of the second example is better than that of the first example of the present invention.

Third Example

Please refer to FIG. 10 which illustrates the third example of the optical imaging lens 1 of the present invention. Please refer to FIG. 11A for the longitudinal spherical aberration on the image plane 71 of the third example; please refer to FIG. 11B for the astigmatic aberration on the sagittal direction; please refer to FIG. 11C for the astigmatic aberration on the tangential direction, and please refer to FIG. 11D for the distortion aberration. The components in the third example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 11 of the first lens element 10 facing toward the object side 2 has a concave portion 13′ in the vicinity of the optical axis and a concave portion 14′ in a vicinity of its periphery.

The optical data of the third example of the optical imaging lens are shown in FIG. 34 while the aspheric surface data are shown in FIG. 35. TTL is 7.869 mm. Fno is 2.28. The image height is 0.576 mm. HFOV is 75 degrees. In particular, the aberration of the third example is better than that of the first example of the present invention.

Fourth Example

Please refer to FIG. 12 which illustrates the fourth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 13A for the longitudinal spherical aberration on the image plane 71 of the fourth example; please refer to FIG. 13B for the astigmatic aberration on the sagittal direction; please refer to FIG. 13C for the astigmatic aberration on the tangential direction, and please refer to FIG. 13D for the distortion aberration. The components in the fourth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 51 of the fifth lens element 50 facing toward the object side 2 has a convex portion 53′ in the vicinity of the optical axis and the image-side surface 62 of the sixth lens element 60 facing toward the image side 3 has a concave portion 67′ in a vicinity of its periphery.

The optical data of the fourth example of the optical imaging lens are shown in FIG. 36 while the aspheric surface data are shown in FIG. 37. TTL is 9.318 mm. Fno is 2.28. The image height is 0.79 mm. HFOV is 67.5 degrees. In particular, the aberration of the fourth example is better than that of the first example of the present invention.

Fifth Example

Please refer to FIG. 14 which illustrates the fifth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 15A for the longitudinal spherical aberration on the image plane 71 of the fifth example; please refer to FIG. 15B for the astigmatic aberration on the sagittal direction; please refer to FIG. 15C for the astigmatic aberration on the tangential direction, and please refer to FIG. 15D for the distortion aberration. The components in the fifth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in the fifth example, the first lens element 10 is made of transparent glass.

The optical data of the fifth example of the optical imaging lens are shown in FIG. 38 while the aspheric surface data are shown in FIG. 39. TTL is 7.977 mm. Fno is 2.28. The image height is 0.527 mm. HFOV is 60 degrees. In particular, the aberration of the fifth example is better than that of the first example of the present invention.

Sixth Example

Please refer to FIG. 16 which illustrates the sixth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 17A for the longitudinal spherical aberration on the image plane 71 of the sixth example; please refer to FIG. 17B for the astigmatic aberration on the sagittal direction; please refer to FIG. 17C for the astigmatic aberration on the tangential direction, and please refer to FIG. 17D for the distortion aberration. The components in the sixth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass and the image-side surface 62 of the sixth lens element 60 facing toward the image side 3 has a concave portion 67′ in a vicinity of its periphery.

The optical data of the sixth example of the optical imaging lens are shown in FIG. 40 while the aspheric surface data are shown in FIG. 41. TTL is 6.796 mm. Fno is 2.28. The image height is 0.668 mm. HFOV is 55 degrees. In particular, the TTL of the sixth example is shorter than that of the first example of the present invention.

Seventh Example

Please refer to FIG. 18 which illustrates the seventh example of the optical imaging lens 1 of the present invention. Please refer to FIG. 19A for the longitudinal spherical aberration on the image plane 71 of the seventh example; please refer to FIG. 19B for the astigmatic aberration on the sagittal direction; please refer to FIG. 19C for the astigmatic aberration on the tangential direction, and please refer to FIG. 19D for the distortion aberration. The components in the seventh example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery, the object-side surface 31 of the third lens element 30 facing toward the object side 2 has a concave portion 34′ in a vicinity of its periphery and the image-side surface 42 of the fourth lens element 40 facing toward the image side 3 has a concave portion 46′ in the vicinity of the optical axis 4 and a concave portion 47′ in a vicinity of its periphery.

The optical data of the seventh example of the optical imaging lens are shown in FIG. 42 while the aspheric surface data are shown in FIG. 43. TTL is 8.196 mm. Fno is 2.28. The image height is 0.561 mm. HFOV is 75 degrees.

Eighth Example

Please refer to FIG. 20 which illustrates the eighth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 21A for the longitudinal spherical aberration on the image plane 71 of the eighth example; please refer to FIG. 21B for the astigmatic aberration on the sagittal direction; please refer to FIG. 21C for the astigmatic aberration on the tangential direction, and please refer to FIG. 21D for the distortion aberration. The components in the eighth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery, the object-side surface 31 of the third lens element 30 facing toward the object side 2 has a concave portion 34′ in a vicinity of its periphery and the image-side surface 42 of the fourth lens element 40 facing toward the image side 3 has a concave portion 47′ in a vicinity of its periphery as well as the image-side surface 62 of the sixth lens element 60 facing toward the image side 3 has a concave portion 67′ in a vicinity of its periphery.

The optical data of the eighth example of the optical imaging lens are shown in FIG. 44 while the aspheric surface data are shown in FIG. 45. TTL is 7.917 mm. Fno is 2.28. The image height is 0.871 mm. HFOV is 75 degrees. In particular, the aberration of the eighth example is better than that of the first example of the present invention.

Ninth Example

Please refer to FIG. 22 which illustrates the ninth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 23A for the longitudinal spherical aberration on the image plane 71 of the ninth example; please refer to FIG. 23B for the astigmatic aberration on the sagittal direction; please refer to FIG. 23C for the astigmatic aberration on the tangential direction, and please refer to FIG. 23D for the distortion aberration. The components in the ninth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery and the object-side surface 31 of the third lens element 30 facing toward the object side 2 has a concave portion 34′ in a vicinity of its periphery.

The optical data of the ninth example of the optical imaging lens are shown in FIG. 46 while the aspheric surface data are shown in FIG. 47. TTL is 7.552 mm. Fno is 2.28. The image height is 0.525 mm. HFOV is 75 degrees. In particular, 1) the HFOV of the ninth example is larger than that of the first example of the present invention, 2) the aberration of the second example is better than that of the first example of the present invention.

Tenth Example

Please refer to FIG. 24 which illustrates the tenth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 25A for the longitudinal spherical aberration on the image plane 71 of the tenth example; please refer to FIG. 25B for the astigmatic aberration on the sagittal direction; please refer to FIG. 25C for the astigmatic aberration on the tangential direction, and please refer to FIG. 25D for the distortion aberration. The components in the tenth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 11 of the first lens element 10 facing toward the object side 2 has a concave portion 13′ in the vicinity of the optical axis 4 and a concave portion 14′ in a vicinity of its periphery and the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery.

The optical data of the tenth example of the optical imaging lens are shown in FIG. 48 while the aspheric surface data are shown in FIG. 49. TTL is 7.005 mm. Fno is 2.28. The image height is 0.385 mm. HFOV is 75 degrees. In particular, 1) the TTL of the tenth example is shorter than that of the first example of the present invention, 2) the aberration of the tenth example is better than that of the first example of the present invention.

Eleventh Example

Please refer to FIG. 26 which illustrates the eleventh example of the optical imaging lens 1 of the present invention. Please refer to FIG. 27A for the longitudinal spherical aberration on the image plane 71 of the eleventh example; please refer to FIG. 27B for the astigmatic aberration on the sagittal direction; please refer to FIG. 27C for the astigmatic aberration on the tangential direction, and please refer to FIG. 27D for the distortion aberration. The components in the eleventh example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery, the object-side surface 31 of the third lens element 30 facing toward the object side 2 has a concave portion 34′ in a vicinity of its periphery and the image-side surface 62 of the sixth lens element 60 facing toward the image side 3 has a concave portion 67′ in a vicinity of its periphery.

The optical data of the eleventh example of the optical imaging lens are shown in FIG. 50 while the aspheric surface data are shown in FIG. 51. TTL is 7.108 mm. Fno is 2.28. The image height is 0.874 mm. HFOV is 75 degrees. In particular, 1) the TTL of the eleventh example is shorter than that of the first example of the present invention, and 2) the aberration of the eleventh example is better than that of the first example of the present invention.

Twelfth Example

Please refer to FIG. 28 which illustrates the twelfth example of the optical imaging lens 1 of the present invention. Please refer to FIG. 29A for the longitudinal spherical aberration on the image plane 71 of the twelfth example; please refer to FIG. 29B for the astigmatic aberration on the sagittal direction; please refer to FIG. 29C for the astigmatic aberration on the tangential direction, and please refer to FIG. 29D for the distortion aberration. The components in the twelfth example are similar to those in the first example, but the optical data such as the curvature radius, the refractive power, the lens thickness, the lens focal length, the aspheric surface or the back focal length in this example are different from the optical data in the first example, and in this example, the first lens element 10 is made of transparent glass, the object-side surface 21 of the second lens element 20 facing toward the object side 2 has a convex portion 23′ in the vicinity of the optical axis 4 and a convex portion 24′ in a vicinity of its periphery and the object-side surface 31 of the third lens element 30 facing toward the object side 2 has a concave portion 34′ in a vicinity of its periphery.

The optical data of the twelfth example of the optical imaging lens are shown in FIG. 52 while the aspheric surface data are shown in FIG. 53. TTL is 7.910 mm. Fno is 2.28. The image height is 0.657 mm. HFOV is 75 degrees. In particular, 1) the spherical aberration of the twelfth example is better than that of the first example of the present invention, and 2) the aberration of the twelfth example is better than that of the first example of the present invention.

Some important ratios in each example are shown in FIG. 54 and in FIG. 55. The distance between the image-side surface 62 of the sixth lens element 60 to the filter 70 along the optical axis 4 is G6F; the thickness of the filter 70 along the optical axis 4 is TF; the distance between the filter 70 to the image plane 71 along the optical axis 4 is GFP; the distance between the image-side surface 62 of the sixth lens element 60 and the image plane 71 along the optical axis 4 is BFL. Therefore, BFL=G6F+TF+GFP.

In the light of the above examples, the inventors observe at least the following features of the optical imaging lens arrangement of the present invention and the corresponding efficacy:

1. The first lens element and the second lens element has negative refractive power to go with the aperture stop which is disposed between the third lens element and the fourth lens element to facilitate the design of an optical imaging lens with larger half field of view. It is preferably to limit the image-side surface of the second lens element with a concave portion in a vicinity of the optical-axis. 2. Optionally, the object-side surface of the second lens element facing toward the object side has a convex part in the vicinity of the optical axis to facilitate the decrease of the EFL to facilitate the design of an optical imaging lens with larger half field of view. 3. Both the object-side surface of the third lens element facing toward the object side and the image-side surface of the third lens element facing toward the image side have convex parts in the vicinity of the optical axis to facilitate the correction the aberration which is caused by the first two lens elements. 4. The object-side surface of the fourth lens element facing toward the object side has a convex part in the vicinity of the optical axis to go with the aperture stop which is disposed between the third lens element and the fourth lens element to facilitate the design of an optical imaging lens of dual wavebands. 5. The object-side surface of the fifth lens element facing toward the object side has a concave part in a vicinity of its circular periphery and the image-side surface of the fifth lens element facing toward the image side has a concave part in the vicinity of the optical axis to facilitate the correction the aberration which is caused by the third lens element and by the fourth lens element. 6. The image-side surface of the sixth lens element facing toward the image side has a convex part in the vicinity of the optical axis to facilitate the adjustment the aberration which is caused by the fifth lens element. 7. With respect to the conditional formulae ALT/T1≤6.70 or AAG/T1≤4.71, by limiting ALT with T1 or AAG with T1, T1 is not too small to fabricate or to assemble the optical imaging lens set. It is preferably to limit 2.9≤ALT/T1≤6.70 or 1.4≤AAG/T1≤4.71 to avoid that T1 is so great to make it harder to design an optical imaging lens with larger half field of view and to increase TTL of the optical imaging lens. 8. When the conditional formula υ1+υ2>υ4+υ5 or υ1+υ4>υ5+υ6 is met, it is advantageous to correct the chromatic aberration of the optical imaging lens and to facilitate the design of an optical imaging lens of dual wavebands.

The following conditional formulae are provided to keep the optical parameters and the focal length of the optical imaging lens in a suitable range so that the parameters are not so great to jeopardize the correction of the entire aberration of the optical imaging lens or too small to fabricate or to assemble the optical imaging lens set.

(T2+T3+T4+T5)/EFL≤5.57,preferably 0.90≤(T2+T3+T4+T5)/EFL≤5.57.  (a)

(T2+T3+T5+T6)/EFL≤5.47, preferably 0.80≤(T2+T3+T5+T6)/EFL≤5.47.  (b)

For the following conditional formulae, they are provided to keep the lens thickness and the air gaps of the optical imaging lens in a suitable range so the parameters are not so great to jeopardize the smaller size of the optical imaging lens or too small to fabricate or to assemble the optical imaging lens set.

(T2+T3+T4+T5)/T1≤4.51, preferably 1.50≤(T2+T3+T4+T5)/T1≤4.51.  (c)

(T2+T3+T5+T6)/T1≤4.41, preferably 1.50≤(T2+T3+T5+T6)/T1≤4.41.  (d)

(G12+T2+T4)/T3≤2.50, preferably 0.30≤(G12+T2+T4)/T3≤2.50.  (e)

(G12+T4+T5)/T3≤2.30, preferably 0.30≤(G12+T4+T5)/T3≤2.30.  (f)

(G12+G23+G56)/(G34+G45)≤6.01, preferably 1.00≤(G12+G23+G56)/(G34+G45)≤6.01.  (g)

(G12+G56+BFL)/(G34+G45)≤7.00, preferably 1.18≤(G12+G56+BFL)/(G34+G45)≤7.00.  (h)

(G12+T2+G23+T3)/T1≤5.81, preferably 2.20≤(G12+T2+G23+T3)/T1≤5.81.  (i)

(T4+G45+T5+G56+T6)/T1≤3.70, preferably 0.80≤(T4+G45+T5+G56+T6)/T1≤3.70.  (j)

(T2+G23+T4+T6)/T1≤5.00, preferably 1.00≤(T2+G23+T4+T6)/T1≤5.00.  (k)

(T2+G23+T4+T6)/(G34+G45)≤7.00, preferably 1.28≤(T2₊ G23₊ T4₊ T6)/(G34₊ G45)≤7.00.  (l)

ALT/T3≤3.80, preferably 1.68≤ALT/T3≤3.80.  (m)

AAG/T3≤2.80, preferably 0.50≤AAG/T3≤2.80.  (n)

TL/T1≤11.50, preferably 5.45≤TL/T1≤11.50.  (o)

TL/T3≤5.42, preferably 1.45≤TL/T3≤5.42.  (p)

The above-mentioned one or more conditions may be optionally combined in the embodiments of the present invention to facilitate the design of the optical imaging lens of similar structure.

In the light of the unpredictability of the optical imaging lens, the present invention suggests the above principles to have a shorter total length of the optical imaging lens, a larger aperture available, better imaging quality or a better fabrication yield to overcome the drawbacks of prior art.

In addition to the above ratios, one or more conditional formulae may be optionally combined to be used in the embodiments of the present invention and the present invention is not limit to this. The curvatures of each lens element or multiple lens elements may be fine-tuned to result in more fine structures to enhance the performance or the resolution. For example, the object-side surface of the first lens element may additionally have a convex portion in the vicinity of the optical axis. The above limitations may be properly combined in the embodiments without causing inconsistency.

The max values or the min values of optional combinations of the above optical parameters are within the ranges of the present invention for the practice of the present invention.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. An optical imaging lens, from an object side toward an image side in order along an optical axis comprising: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element, said first lens element to said sixth lens element each having an object-side surface facing toward said object side to allow an imaging ray to pass through as well as an image-side surface facing toward said image side to allow said imaging ray to pass through, wherein: said first lens element has negative refractive power; said second lens element has negative refractive power; said object-side surface of said third lens element has a convex portion in a vicinity of said optical-axis and said image-side surface of said third lens element has a convex portion in a vicinity of said optical-axis; said object-side surface of said fourth lens element has a convex portion in a vicinity of said optical-axis; said object-side surface of said fifth lens element has a concave portion in a vicinity of its periphery and said image-side surface of said fifth lens element has a concave portion in a vicinity of said optical-axis; said image-side surface of said sixth lens element has a convex portion in a vicinity of said optical-axis, and said optical imaging lens exclusively has six lens elements with refractive power, ALT is a total thickness of all six lens elements and said first lens element has a first lens element thickness T1 to satisfy ALT/T1≤6.70.
 2. The optical imaging lens of claim 1, wherein EFL is an effective focal length of the optical imaging lens set, said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis and said fifth lens element has a fifth lens element thickness T5 along said optical axis to satisfy (T2+T3+T4+T5)/EFL≤5.57.
 3. The optical imaging lens of claim 1, wherein said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, said fifth lens element has a fifth lens element thickness T5 along said optical axis and said sixth lens element has a sixth lens element thickness T6 along said optical axis to satisfy (T2+T3+T5+T6)/T1≤4.41.
 4. The optical imaging lens of claim 1, wherein said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis and an air gap G12 between said first lens element and said second lens element along said optical axis to satisfy (G12+T2+T4)/T3≤2.50.
 5. The optical imaging lens of claim 1, wherein an air gap G12 between said first lens element and said second lens element along said optical axis, an air gap G23 between said second lens element and said third lens element along said optical axis, an air gap G34 between said third lens element and said fourth lens element along said optical axis, an air gap G45 between said fourth lens element and said fifth lens element along said optical axis and an air gap G56 between said fifth lens element and said sixth lens element along said optical axis to satisfy (G12+G23+G56)/(G34+G45)≤6.01.
 6. The optical imaging lens of claim 1, wherein said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, an air gap G12 between said first lens element and said second lens element along said optical axis and an air gap G23 between said second lens element and said third lens element along said optical axis to satisfy (G12+T2+G23+T3)/T1≤5.81.
 7. The optical imaging lens of claim 1, wherein said second lens element has a second lens element thickness T2 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis, said sixth lens element has a sixth lens element thickness T6 along said optical axis and an air gap G23 between said second lens element and said third lens element along said optical axis to satisfy (T2+G23+T4+T6)/T1≤5.00.
 8. The optical imaging lens of claim 1, wherein said third lens element has a third lens element thickness T3 along said optical axis to satisfy ALT/T3≤3.80.
 9. The optical imaging lens of claim 1, wherein TL is a distance between said object-side surface of said first lens element and said image-side surface of said sixth lens element along said optical axis to satisfy TL/T1≤11.50.
 10. The optical imaging lens of claim 1, wherein said first lens element has an Abbe number υ1, said second lens element has an Abbe number υ2, said fourth lens element an Abbe number υ4 and said fifth lens element has an Abbe number υ5 to satisfy υ1+υ2>υ4+υ5.
 11. An optical imaging lens, from an object side toward an image side in order along an optical axis comprising: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element, said first lens element to said sixth lens element each having an object-side surface facing toward said object side to allow an imaging ray to pass through as well as an image-side surface facing toward the image side to allow said imaging ray to pass through, wherein: said first lens element has negative refractive power; said second lens element has negative refractive power and said image-side surface of said second lens element has a concave portion in a vicinity of said optical-axis; said object-side surface of said third lens element has a convex portion in a vicinity of said optical-axis and said image-side surface of said third lens element has a convex portion in a vicinity of said optical-axis; said object-side surface of said fourth lens element has a convex portion in a vicinity of said optical-axis; said object-side surface of said fifth lens element has a concave portion in a vicinity of its periphery and said image-side surface of said fifth lens element has a concave portion in a vicinity of said optical-axis; said image-side surface of said sixth lens element has a convex portion in a vicinity of said optical-axis; and said optical imaging lens exclusively has six lens elements with refractive power, AAG is a sum of all five air gaps between each lens element from said first lens element to said sixth lens element and said first lens element has a first lens element thickness T1 to satisfy AAG/T1≤4.71.
 12. The optical imaging lens of claim 11, wherein EFL is an effective focal length of the optical imaging lens set, said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, said fifth lens element has a fifth lens element thickness T5 along said optical axis and said sixth lens element has a sixth lens element thickness T6 along said optical axis to satisfy to satisfy (T2+T3+T5+T6)/EFL≤5.47.
 13. The optical imaging lens of claim 11, wherein said second lens element has a second lens element thickness T2 along said optical axis, said third lens element has a third lens element thickness T3 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis and said fifth lens element has a fifth lens element thickness T5 along said optical axis to satisfy (T2+T3+T4+T5)/T1≤4.51.
 14. The optical imaging lens of claim 11, wherein said third lens element has a third lens element thickness T3 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis, said fifth lens element has a fifth lens element thickness T5 along said optical axis and an air gap G12 between said first lens element and said second lens element along said optical axis to satisfy (G12+T4+T5)/T3≤2.30.
 15. The optical imaging lens of claim 11, wherein BFL is a distance between said image-side surface of said sixth lens element and an image plane along said optical axis, an air gap G12 between said first lens element and said second lens element along said optical axis, an air gap G34 between said third lens element and said fourth lens element along said optical axis, an air gap G45 between said fourth lens element and said fifth lens element along said optical axis and an air gap G56 between said fifth lens element and said sixth lens element along said optical axis to satisfy (G12+G56+BFL)/(G34+G45)≤7.00.
 16. The optical imaging lens of claim 11, wherein said fourth lens element has a fourth lens element thickness T4 along said optical axis, said fifth lens element has a fifth lens element thickness T5 along said optical axis and said sixth lens element has a sixth lens element thickness T6 along said optical axis, an air gap G45 between said fourth lens element and said fifth lens element along said optical axis and an air gap G56 between said fifth lens element and said sixth lens element along said optical axis to satisfy (T4+G45+T5+G56+T6)/T1≤3.70.
 17. The optical imaging lens of claim 11, wherein said second lens element has a second lens element thickness T2 along said optical axis, said fourth lens element has a fourth lens element thickness T4 along said optical axis, said sixth lens element has a sixth lens element thickness T6 along said optical axis and an air gap G23 between said second lens element and said third lens element along said optical axis, an air gap G34 between said third lens element and said fourth lens element along said optical axis and an air gap G45 between said fourth lens element and said fifth lens element along said optical axis to satisfy (T2+G23+T4+T6)/(G34+G45)≤7.00.
 18. The optical imaging lens of claim 11, wherein said third lens element has a third lens element thickness T3 along said optical axis to satisfy AAG/T3≤2.80.
 19. The optical imaging lens of claim 11, wherein TL is a distance between said object-side surface of said first lens element and said third lens element has a third lens element thickness T3 along said optical axis to satisfy TL/T3≤5.42.
 20. The optical imaging lens of claim 11, wherein said first lens element has an Abbe number υ1, said fourth lens element an Abbe number υ4, said fifth lens element has an Abbe number υ5 and said sixth lens element has an Abbe number υ6 to satisfy υ1+υ4>υ5+υ6. 